This invention relates to silencing equipment for fans, and more specifically, to an improved fan silencer having removable covers to permit fast and easy replacement of sound absorbing or barrier materials (herein referred to as insulating materials) contained therein.
In industrial applications, exhaust fans for moving large volumes of air are widely used for drawing harmful or annoying fumes, vapors, mists, etc. away from a working area. Unfortunately, these high volume exhaust fans often operate at relatively high noise levels which can have harmful effects upon persons in the working area. Governmental agencies have increasingly recognized the possible harmful effects from high levels of industrial noise, and are becoming increasingly involved in the regulation of such noise. As a result, a wide variety of fan silencing equipment has been proposed to absorb exhaust fan noise, and thereby reduce noise in the working area to a safe level.
While a wide variety of silencers for exhaust fans are available throughout the prior art, such silencers typically comprise a silencer housing mounted along ductwork between the fan and the working area. The housing contains an insulating, or noise absorbing, material and is designed to allow air flow therethrough while providing adequate noise control. However, in many industrial applications, the air drawn through the silencer contains large quantities of harmful vapors or moisture. This is especially true, for example, when the exhaust fan is used to draw air from a spray painting work station. The drawn air tends to carry paint solvent and moisture vapors and particles through the fan silencer to saturate the silencer insulating material and coat the silencer housing with paint. This saturation significantly reduces the noise deadening efficiency of the fan silencer, and thereby results over a period of time in increased noise levels at the working area. Unfortunately, it has heretofore not been possible to replace the silencer insulating material or to clean the silencer housing without removing the entire silencer from the ductwork. Such removal of the silencer is a time consuming procedure, and results in the work station being unusable until the silencer is replaced.
It is therefore desirable to provide an improved fan silencer which has removable housing walls to allow fast and easy replacement of insulating material therein, and fast and easy cleaning of the housing walls. Further, it is desirable to provide such a silencer wherein said replacement of insulating material and cleaning of housing walls can be accomplished without removing the silencer from the ductwork.